How to simulate engines spraying a fluid?
Particles:

For the fluid being blown by a fan/turbine, you could try a particle system.
For a really thin fluid/mist, simulating it as a bunch of spheres is probably overkill. 

Instead you could try using textured planes (or Billboards):


Add a emitter plane and rotate it 90 so it is standing on its edge:


Add a Particle system to the emitter plane in Properties > Particles.

Blender Internal:

For BI you can use Billboard particles (these don't work in cycles):



Cycles:

For cycles you will need to use a slightly different technique to render billboard objects:


Set the particles to use an object for rendering in Particles > Render > Object.
Add another plane and add a Track To constraint to make it track to the camera (Select the plane and then the camera, then press CtrlT> Track To constraint):


Set the To and Up settings of the constraint in (with the plane active) Properties > Constraints so that the plane faces the camera:


With the emitter plane active, set the Dupli Object to the plane with the constraint and enable Rotation so that the particles will use the rotation defined by the constraint:



Lower the influence of the scene gravity in Particles > Field Weights > Gravity:


Add a Wind force field (ShiftA> Add > Force field > Wind) and rotate it 90 degrees so it is parallel to the emitter plane:

  

You may want to tweak the strength in Properties > Physics.
Add a Vortex force field and rotate it 90 like the wind force:




Smoke:

If the fluid is really thin, you may want to try a Smoke Simulation.

Note that until Cycles has volumetrics (planned for 2.7) you will not be able to render the smoke in Cycles.